In the market, the casting accuracy of aluminum alloy wheels is increasingly improved by finished automobile manufacturers. This is due to that the balance and aesthetics of aluminum alloy wheels greatly depend on whether the product is accurately realized according to the dimensions of design drawings in the casting and machining processes of aluminum alloy.
In the manufacturing of the aluminum alloy wheels, the low-pressure casting is a relatively mature technology. In the actual production, it needs to cool the low-pressure casted mold (such as side die) during the casting process. The split-type side die is adopted in water-cooling of low-pressure casted wheel mold, which has better effect in practical application. In industrial productions, the split-type side die is widely applied. This is due to its simple assembly and lower production and repairing costs.
However, the split-type side die has a large temperature difference between areas close to and away from water-cooling. Specifically, the temperature of the water-cooling portion is lower, the shrinkage of the mold at this portion is more serious; the temperature of the area away from the water-cooling is higher and the shrinkage of the mold at this portion is less than that at the previous portion. Deformation difference of the split-type side die seriously affects the side die and the lower die which are accurately matched, causing the problems such as flashing, aluminum-sticking of the matching surfaces. Because the structure and fastening means of the split-type mold of low-pressure cast aluminum wheel are complicated, it is hard to explicitly calculate and estimate the factors of thermal expansion and cold contraction of the split-type mold, it is difficult to overcome the casting dimensional error caused by deformation of the mold by providing allowance in the design, and it also brings great difficulties to subsequent machining process.
Meanwhile, the partial shrinkage phenomenon caused by thermal expansion and cold contraction of the mold causes the mold easily to be damaged and reduces the lifetime of the mold. In the field of casting, the mold cost is a very key part of the casting cost. Viewed from the production practice, the split-type water-cooling mold is usually damaged from the middle part of the split-type side die at first, such as deformation and damage of the mold caused by thermal fatigue, thermal deformation, extrusion, etc.
In this filed, it is always hoped to design a new type of mold to overcome this problem, increase the lifetime of the mold, decrease the mold cost in the production, improve the dimensional accuracy of wheel in the casting process as much as possible and overcome the defects such as flashing, aluminum-sticking and so on. If this problem is overcome, the service life of the mold can be prolonged, the work-hours and consumables can be saved in the machining, the manufacturing cost of the wheel can be reduced, the utilization efficiency of metal can be increased and the profitability of enterprise can be improved.